Air circulation controller with short-cycle prevention capability
First Claim
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1. A method for controlling the circulation of air for improving indoor air quality of a building having an environmental control system including a system fan, comprising the steps of:
- a) receiving system settings from a user interface indicating that a user desires controlled air circulation;
b) engaging the system fan for a circulating air based upon the system settings;
c) predicting future operation of the system fan due to operation of the environmental control system;
d) modifying the first interval of time as a function of the predicted operation of the environmental control system in order to prevent nuisance short cycling of the system fan;
e) disengaging the system fan for a second interval of time such that the ratio of the first interval of time to the second interval of time achieves a minimum desired circulation cycle; and
f) continuously repeating steps b) through e) while the system settings circulation control mode is selected.
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Abstract
A method and system for improving indoor air quality by controlling the circulation of air by a system fan of a conventional environmental control system in order to achieve a minimum circulation cycle. The method and system prevent nuisance short cycling of the system fan by extending the circulation cycle when the method and system predict the system fan will be activated by the environmental control system for heating or cooling shortly after the termination of the controlled circulation.
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Citations
13 Claims
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1. A method for controlling the circulation of air for improving indoor air quality of a building having an environmental control system including a system fan, comprising the steps of:
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a) receiving system settings from a user interface indicating that a user desires controlled air circulation; b) engaging the system fan for a circulating air based upon the system settings; c) predicting future operation of the system fan due to operation of the environmental control system; d) modifying the first interval of time as a function of the predicted operation of the environmental control system in order to prevent nuisance short cycling of the system fan; e) disengaging the system fan for a second interval of time such that the ratio of the first interval of time to the second interval of time achieves a minimum desired circulation cycle; and f) continuously repeating steps b) through e) while the system settings circulation control mode is selected. - View Dependent Claims (2)
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3. A method of operating a system fan in a heating, ventilating, and air conditioning (HVAC) system of the type which has a temperature controller which generates an anticipator temperature having a rise and fall rate according to an anticipator factor based on thermal characteristics of the HVAC system, in order to circulate air in a ventilation system of a building to improve the indoor air quality, comprising the steps of:
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a) receiving system settings from a user interface indicating that a user has selected a controlled air circulation mode; b) engaging the system fan for circulating air based upon the selected mode; c) maintaining the system fan engaged for a first interval of time; d) predicting the state of the system fan as will be controlled by the HVAC system at a predetermined future time; e) modifying the first interval of time of the maintaining step based on the predicted state of the system fan to prevent nuisance short cycling of the system fan; f) disengaging the system fan for a second interval of time such that the ratio of the first interval of time to the second interval of time achieves the desired circulation cycle; and g) continuously repeating steps b) through f) while the controlled air circulation mode is selected. - View Dependent Claims (4, 5, 6, 7)
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8. A method of operating a system fan in a heating, ventilating, an air conditioning (HVAC) system of the type which has a temperature controller which generates an anticipator temperature having a rise and fall rate according to an anticipator factor based on thermal characteristics of the HVAC system, in order to circulate air in a ventilation system of a building to improve the indoor air quality, comprising the steps of:
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a) receiving system settings from a user interface indicating that a user desires controlled air circulation; b) decreasing a count by a first constant if the HVAC system is not active; c) increasing the count by a second constant if the HVAC system is active where the ratio of the second constant to the first constant determines a duty cycle of the system fan; d) disengaging the system fan when the count reaches an upper threshold; e) engaging the system fan when the count reaches a lower threshold; f) continuously repeating steps b) through e) while circulation control mode is selected. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification